US Patent 9873561 Item retrieval using a robotic drive unit

Disclosed are various embodiments that may facilitate retrieval of items from a storage location. A robotic drive unit transports a receptacle to be proximate to a target storage unit that comprises an item. The robotic drive unit moves an item mover to transfer the item from the target storage unit to the receptacle. The robotic drive unit transports the item in the receptacle to a destination.